The Collaborative International Dictionary of English v.0.48:

Superabundance \Su`per*a*bun"dance\, n. [L. superabundantia: cf.
   OF. superabondance.]
   The quality or state of being superabundant; a superabundant
   quantity; redundancy; excess.
   [1913 Webster]

WordNet (r) 3.0 (2006):

superabundance
    n 1: a quantity that is more than what is appropriate; "four-
         year-olds have an overabundance of energy"; "we received an
         inundation of email" [syn: overabundance, overmuch,
         overmuchness, superabundance]

Moby Thesaurus II by Grady Ward, 1.0:

144 Moby Thesaurus words for "superabundance":
   abundance, acres, affluence, ample sufficiency, ampleness,
   amplitude, avalanche, bags, barrels, bonanza, bountifulness,
   bountiousness, bumper crop, bushel, cloud of words, copiousness,
   countlessness, deluge, diffuseness, diffusion, diffusiveness,
   effusion, effusiveness, embarras de richesses, enough,
   extravagance, extravagancy, exuberance, fecundity, fertility,
   flood, flow, fluency, foison, formlessness, fructiferousness,
   fruitfulness, full measure, fullness, generosity, generousness,
   great abundance, great plenty, gush, gushing, inundation,
   landslide, lavishness, liberality, liberalness, load, logorrhea,
   lots, lushness, luxuriance, macrology, mass, maximum,
   money to burn, more than enough, mountain, much, multitude, myriad,
   myriads, numerousness, ocean, oceans, opulence, opulency, outpour,
   outpouring, overabundance, overaccumulation, overbounteousness,
   overcopiousness, overdose, overflow, overlavishness,
   overluxuriance, overmeasure, overmuchness, overnumerousness,
   overplentifulness, overplenty, overpopulation, overprofusion,
   oversufficiency, oversupply, palilogy, peck, plenitude,
   plenteousness, plentifulness, plenty, pleonasm, plethora,
   pregnancy, prevalence, procreativeness, prodigality,
   productive capacity, productiveness, productivity, profuseness,
   profusion, prolificacy, prolificity, quantities, quantity,
   rampancy, rankness, redundancy, reiteration, reiterativeness,
   repetition for effect, repetitiveness, repleteness, repletion,
   rich harvest, rich vein, richness, riot, riotousness, scads, sea,
   shower, spate, stream, substantiality, substantialness,
   superfluity, superflux, swarmingness, talkativeness, tautology,
   teeming womb, teemingness, tirade, tons, volume, wealth, world,
   worlds